Search UvA-DARE

Catecholamine-Mediated Increases in Gain Enhance the Precision of Cortical Representations

Journal

The Journal of Neuroscience

Volume | Issue number

36 | 21

Pages (from-to)

5699-5708

Document type

Article

Faculty

Faculty of Social and Behavioural Sciences (FMG)

Institute

Psychology Research Institute (PsyRes)

Abstract

Neurophysiological evidence suggests that neuromodulators, such as norepinephrine and dopamine, increase neural gain in
target brain areas. Computational models and prominent theoretical frameworks indicate that this should enhance the precision
of neural representations, but direct empirical evidence for this hypothesis is lacking. In two functional MRI studies, we
examine the effect of baseline catecholamine levels (as indexed by pupil diameter and manipulated pharmacologically) on the
precision of object representations in the human ventral temporal cortex using angular dispersion, a powerful, multivariate
metric of representational similarity (precision). We first report the results of computational model simulations indicating
that increasing catecholaminergic gain should reduce the angular dispersion, and thus increase the precision, of object representations
from the same category, as well as reduce the angular dispersion of object representations from distinct categories when distinct-category
representations overlap. In Study 1 (N = 24), we show that angular dispersion covaries with pupil diameter, an index of baseline
catecholamine levels. In Study 2 (N = 24), we manipulate catecholamine levels and neural gain using the norepinephrine transporter
blocker atomoxetine and demonstrate consistent, causal effects on angular dispersion and brain-wide functional connectivity.
Despite the use of very different methods of examining the effect of baseline catecholamine levels, our results show a striking
convergence and demonstrate that catecholamines increase the precision of neural representations.

SIGNIFICANCE STATEMENT:
Norepinephrine and dopamine are among the most widely distributed and ubiquitous neuromodulators in the mammalian brain and
have a profound and pervasive impact on cognition. Baseline catecholamine levels tend to increase with increasing task engagement
in tasks involving perceptual decisions, yet there is currently no direct evidence of the specific impact of these increases
in catecholamine levels on perceptual encoding. Our results fill this void by showing that catecholamines enhance the precision
of encoding cortical object representations, and by suggesting that this effect is mediated by increases in neural gain, thus
offering a mechanistic account of our key finding.

Disclaimer/Complaints regulations

If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let
the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible
and/or remove it from the website. Please Ask the Library, or send a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands.
You will be contacted as soon as possible.